Vehicles such as a passenger vehicle and a freight vehicle are mounted with various electronic devices constituting an air conditioner, a wiper, a power window and such. These electronic devices are electrically-connected to an electronic control unit (ECU) including a computer and such by a wire harness. Electric power and a control signal and such are transmitted between these electronic devices and the ECU via the wire harness. Such wire harness includes a plurality of electric wires and a connector for receiving a terminal fitting connected to an end of the electric wire.
Conventionally, the ECU includes an input-output portion per electronic device connected to the ECU, and thus it requires a dedicated electric wire per electronic device. Thus, as the number of electronic devices controlled by the ECU increases, the number of electric wires of the wire harness for connecting the ECU with the electronic devices is increased. As a result, there are problems of an increase in the cost of the wire harness, a decrease in wiring property and an increase in weight, to name a few.
The inventors of the present invention had proposed a technology for solving such problem, as disclosed in Patent Literature 1. A wire harness provided to an electronic device control system disclosed in Patent Literature 1 as well as an electronic device control system 101 shown in FIG. 12, for example, are provided with a relay connector 106 having a communication control mechanism, the relay connector 106 being arranged to relay the communication between a plurality of electronic devices 103 and an ECU (not shown).
The relay connector 106 is provided between the plurality of electronic devices 103 and the ECU. The communication between the ECU and the relay connector 106 is multiplexed, and the relay connector 106 transmits a control signal from the electronic control unit to the electronic device 103 corresponding to the identification data contained in said control signal. In this manner, the communication between the ECU and the relay connector 106 is multiplexed. Thus, the electronic control unit and the relay connector 106 can be connected to each other without using a dedicated electric wire per electronic device 103, thereby reducing the number of electric wires connecting the electronic control unit with the relay connector 106.
However, in the electronic device control system 101 shown in FIG. 12, the relay connector 106 is provided with a chip which functions as a power supply unit for supplying electric power to the electronic devices 103 in accordance with the control signal from the electronic control unit transmitted to the electronic device 103 corresponding to the identification data. Thus, it is necessary to provide the dedicated chip per electronic device 103. Consequently, as the number of electronic devices 103 increases, the number of chips mounted to the relay connector 106 is increased. Thus, there is a problem that the size of the relay connector 106 itself is increased, causing a decrease in mountability to the vehicle.
Furthermore, it is necessary to change the kind of the chip or the chip itself mounted on the relay connector 106 when the specification is changed, for example when the number of electronic devices 103 is increased or decreased or the power of the electronic device 103 is changed. Thus, it is necessary to prepare the relay connectors 106 mounted with the chips corresponding to the respective combinations of these electronic devices 103 to be mounted on the vehicle. Thus, it is difficult to standardize the relay connector 106, and thus the kind of the relay connector 106 is increased, thereby increasing the cost.